On 2006-05-08, Howard Nelson wrote:
different reasons). I have experienced -500fpm rate of climb in a C182 with
1/2 fuel and two on board 65Knot IAS in May departing Truckee due to

From someone who flies gliders - do NOT fly slowly in sink. It will just
prolong the amount of time you spend in the sink (resulting in a greater
altitude loss). You will of course have to work out the speed to fly for
your particular aircraft -vs- the observed sink rate to determine the
best speed to fly.

For example, imagine a plane that climbs at 1000 fpm in still air at
60kts, and 700 fpm at 120kts.

You're at full power and in sink at 60kts, and you're showing 500fpm
down. Imagine the sink lasts for 4 miles. It'll take you 4 minutes (1
mile per minute) to get through, and you will lose 2000 feet. The air is
sinking at 1500fpm.

If you instead fly this particular plane at 120 knots through the same
sink, you'll only spend 2 minutes to get through it, and your rate of
descent will be 800 fpm - and you'll come out of the sink having lost
1600 feet (and therefore be 400 feet higher than if you'd flown through
the sink slowly).

The example here is obviously contrived (for easy calculation) - but you
can work out some scenarios based on the performance of your plane to
figure out the best speed to fly in sink.

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